1. Field of the Invention
The present invention relates to a touch sensing device and a method thereof that can accurately sense touches generated in a plurality of sensing electrodes with one or a small number of signal converting units, by sequentially detecting sensed signals.
2. Description of the Related Art
Touch sensing devices such as a touch screen, a touch pad, and the like, as input devices attached to a display apparatus to provide an intuitive input method to a user, have been widely applied to a variety of electronic apparatuses such as a cellular phone, a personal digital assistant (PDA), a vehicle navigation unit, and the like, in recent years. In particular, recently, with an increase in demand for smart phones, the rate at which touch screens have been adopted as touch sensing device elements capable of providing various input methods in a limited form factor has increased on a day by day basis.
Touch screens adopted in portable apparatuses may be largely classified into resistive type and capacitive type touch screens, according to a touch sensing method. Since capacitive type touch screens have advantages, in that they may have an extended life-span, and various input methods and gestures can be easily implemented therein, and thus, the adoption rate thereof has steadily increased. In particular, it is easier to implement a multi-touch interface in a capacitive type touch screen than in a resistive type touch screen, and as a result, the capacitive type touch screen is widely applied to electronic apparatuses, such as smart phones, and the like.
The capacitive type touch screen is constituted by a sensing circuit for detecting variations in capacitance generated from an electrode and a signal processor determining touches by signal-processing the variations in capacitance detected by the sensing circuit. However, due to the characteristics of the touch screen primarily applied to portable apparatuses, hardware space provided for the touch screen is limited, and power consumed by the touch screen cannot but be limited to a predetermined range for efficient power management of the overall portable apparatus. Accordingly, connecting a plurality of respective signal processors to the sensing circuits, themselves individually connected to a plurality of electrodes, may cause a problem in terms of limited form factor and power management.